Process of manufacture of particles with a natural calcium carbonate and ethylene acrylic acid salts base, suspensions and dry pigments obtained, their uses

ABSTRACT

The present invention consists of a process of preparation of at least one mineral matter and/or of at least one pigment, including a calcium carbonate made at once partially organophilic and partially hydrophilic, in which the carbonate is blended and/or ground and/or concentrated in an aqueous medium, in the presence of at least one salt of ethylene acrylic acid, one dispersing agent and/or one grinding aid agent, which is introduced before and/or during this treatment stage. Another object of the invention lies in the aqueous dispersions and suspensions of calcium carbonate thus obtained. They may be dried and the dry pigments obtained also constitute an object of the invention. Use of these aqueous dispersions and these dry pigments in the field of plastic, paints and paper constitutes another object of the invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of U.S. application Ser. No. 12/087,555, filed Sep.12, 2008, which is a U.S. National phase of PCT Application No.PCT/IB2007/000076, filed Jan. 9, 2007, which claims priority to FrenchApplication No. 0600491, filed Jan. 19, 2006, the contents of which arehereby incorporated by reference.

The first object of the present invention consists of a process ofpreparation of at least one mineral matter and/or at least one pigment,including a natural and/or precipitated calcium carbonate,preferentially natural, made at once partially organophilic andpartially hydrophilic, and including the stages of:

-   -   a) supplying at least one mineral matter and/or at least one        pigment containing natural and/or precipitated calcium        carbonate, in a dry form or in the form of an aqueous dispersion        and/or suspension,    -   b) possibly dry grinding and/or grinding in an aqueous medium        the mineral matter and/or the pigment resulting from stage a),    -   c) treating the mineral matter and/or the pigment resulting from        stage a) and/or from stage b),    -   d) possibly drying the mineral matter and/or the pigment        resulting from stage a) and/or b) and/or c),        characterised in that:    -   treatment stage c) corresponds to a stage of blending in an        aqueous medium and/or of grinding in an aqueous medium, and/or        of concentration in an aqueous medium, of the mineral matter        and/or the pigment obtained from stage a) and/or from stage b),        in the presence of at least one salt of ethylene acrylic acid,    -   a dispersing agent and/or grinding aid agent is introduced        before and/or during the treatment stage c).

A second object of the present invention lies in the aqueous suspensionsand dispersions obtained by the said process.

A third object of the present invention lies in the dry productsobtained by the said process.

A fourth object of the present invention lies in the use of the saidaqueous suspensions and the said aqueous dispersions and the said dryproducts in the manufacture of plastics, paints and papers, and notablyin plastic or paper coatings, and also in plastic or paper massfillings.

The aim of the process is essentially the processing and/or economicproduction of a mineral matter and/or a pigment including a naturaland/or precipitated calcium carbonate.

The process according to the invention notably enables the skilled manin the art to obtain a dispersion of mineral matter and/or of pigmenttreated in this manner with a high dry extract (an expression which willbe repeated throughout the present Application, and defined as thepercentage by dry weight of mineral matter and/or of pigment relative tothe total weight of the said dispersion).

A high dry extract, and notably one greater than 65%, preferentially70%, very preferentially greater than 75%, of the total weight of thesaid dispersion leads to a reduction of the costs of transport of such adispersion, and to a reduction of the drying costs of such a dispersion.

The process according to the invention notably enables such dry extractsto be obtained, whilst retaining for the said dispersion advantageousrheological properties, since the said dispersion remains easily able tobe handled, and which prevents the significant presence of agglomerates.

A second aim is to give the skilled man in the art the possibility oftreating the mineral matter and/or the pigment containing a naturaland/or precipitated calcium carbonate to make it at once partiallyorganophilic and partially hydrophilic, both during a grinding stage,and during a blending stage, and during a concentration stage, which arethe stages traditionally implemented during the overall process ofmanufacture of an aqueous dispersion of mineral matter: these differentpossibilities all constitute flexibility made available to the skilledman in the art.

A calcium carbonate made organophilic in this manner may be usedadvantageously in the plastics field; furthermore, its hydrophiliccharacter will enable it to be dispersed at high concentration in water,i.e. aqueous dispersions or suspensions of calcium carbonate to beobtained of which the dry weight content of mineral matter will notablybe greater than 65% of their total weight, whilst having advantageousrheological properties without the formation of agglomerates.

In plastics, such as notably thermoplastic resins or thermosettingresins, mineral matter and/or pigments are commonly incorporated, suchas, for example, natural or precipitated calcium carbonate, thedolomites, magnesium hydroxide, kaolin, talc, gypsum, or again titaniumdioxide. This mineral matter and/or these pigments can improveparticular properties of these plastics, such as, in the case of the useof calcium carbonate in PVC, increased rigidity, improved thermalexchanges during extrusion, or again reduced deposit on die-removal. TheApplicant may in this respect quote the document “The use of calciumcarbonate to enhance the physical properties of rigid vinyl products”(Society of Plastic Engineers, Conf., 12-14 Oct. 1999). Furthermore, itis also common to replace part of the plastic resins, which areexpensive materials, by these pigments and/or this mineral matter.

In connection with the use of calcium carbonate in plastics, the skilledman in the art—who is a manufacturer of mineral matter notably with aview to its use in plastics—knows that in order to improve thecompatibility of the said carbonate with the plastic in which it isincorporated it is necessary to treat the calcium carbonate. In relationthereto, it has been known for many years to use derivatives of fattyacids as a treatment agent of calcium carbonate, since these fatty acidsnotably have 10 to 20 carbon atoms, and more specifically 16 to 18carbon atoms, in a saturated carbon structure (such as stearic acid),palmitic acid and/or stearic acid and their salts, which are the agentor agents preferentially used by the skilled man in the art.

It is important to indicate that the calcium carbonate is preparedaccording to various stages of manufacture in an aqueous medium, such asstages of dispersion, grinding or again concentration. The productresulting from the stages is an aqueous dispersion or suspension ofcalcium carbonate, possibly containing different dispersing agentsand/or grinding aid agents and/or treatment agents introduced in thecourse of these different stages.

Generally, when stearic acid is added (either in the molten state, or inthe form of an emulsion) into a dispersion or suspension of calciumcarbonate, or to dry calcium carbonate, an additional stage ofdisaggregation must be undertaken following this addition.

In the case of the use of an emulsion of stearic acid, in which anemulsifier may be introduced in order to stabilise this emulsion, thepresence of the emulsifier may cause the destabilisation of thedispersion or of the suspension of calcium carbonate, which leads to theformation of flocculated particles and/or floating particles. Thisemulsifier has the additional drawback that it causes foam to be createdin the dispersion or the suspension.

This brings up a first drawback relating to the use of stearic acid: itrequires the addition of additional stages and/or additives, sometimeswith negative consequences during the treatment process.

Nor does selecting a treatment undertaken with salts of stearic acid, asneutralised with calcium ions, lead to the solution sought by theskilled man in the art: it also has the drawback of leading to thecreation of foam in the dispersion or suspension of calcium carbonate.

Finally, it appears that the use of stearic acid or of its salts doesnot enable aqueous suspensions or dispersions of calcium carbonate to beobtained having a concentration by weight of dry mineral matter greaterthan 65% of the total weight of the said dispersion or suspension with ausable viscosity and/or without the creation of agglomerates which leadto the presence of residues retrieved on the filtration screens. Andcalcium carbonate is commonly manufactured according to the previouslydescribed stages, transported in the form of an aqueous dispersion orsuspension, possibly stored in this same form, and finally dried beforebeing incorporated in the plastic. For economic reasons, it is essentialfor the skilled man in the art to manufacture and deliver to the endtransformer an aqueous dispersion or suspension of calcium carbonatehaving as high as possible a dry extract, whilst maintaining asatisfactory viscosity and/or without significant creation ofagglomerates, and thus residues retrieved on the screen, which the useof stearic acid or its salts does not permit.

Seeking to resolve these different drawbacks relating to the use ofstearic acid or of its salts, in order to treat, so as to make it atonce partially organophilic and partially hydrophilic, a mineral matter(and notably calcium carbonate) with a view to its incorporation inplastics and with a view to manufacturing it economically, the Applicanthas developed a new process for preparation of at least one mineralmatter and/or at least one pigment including natural and/or precipitatedcalcium carbonate which is at once partially organophilic and partiallyhydrophilic, and comprising the stages of:

-   -   a) supplying at least one mineral matter and/or one pigment        containing natural and/or precipitated calcium carbonate, in a        dry form or in the form of a dispersion and/or an aqueous        suspension,    -   b) possibly dry grinding and/or grinding in an aqueous medium        the mineral matter and/or the pigment resulting from stage a),    -   c) treating the mineral matter and/or the pigment resulting from        stage a) and/or from stage b),    -   d) possibly drying the mineral matter and/or the pigment        resulting from stage a) and/or b) and/or c),        characterised in that:    -   treatment stage c) corresponds to a stage of blending in an        aqueous medium and/or of grinding in an aqueous medium, and/or        of concentration in an aqueous medium, of the mineral matter        and/or the pigment obtained from stage a) and/or from stage b),        in the presence of at least one salt of ethylene acrylic acid,    -   a dispersing agent and/or grinding aid agent is introduced        before and/or during the treatment stage c).

Such a process therefore enables, in a very surprising manner, thetreatment agent to be incorporated in order to manufacture suspensionsof natural and/or precipitated calcium carbonate with dry extractshigher than those obtained by the processes of the prior art usingstearic acid or its salts, whilst maintaining a satisfactory viscosityand/or without the significant creation of agglomerates and thusresidues retrieved on the screen, and without the drawbacks of thisprior art.

It is notably very surprising that, if the salts of ethylene acrylicacid are added during or after the addition of dispersing agent, itssalts do not influence in a negative fashion the rheological propertiesof the dispersions obtained: indeed, one succeeds surprisingly, usingthe process according to the invention, in obtaining high dry extracts(notably greater than 65%) with satisfactory rheological properties andwithout the formation of agglomerates.

At the same time, it is very surprising that the dispersing agent (whichis added before or during the introduction of the ethylene acrylic acidsalts) does not prevent the interaction between the said salts and thesurface of the calcium carbonate in order to make it organophilic:indeed, one succeeds surprisingly, using the process according to theinvention, in manufacturing calcium carbonate particles which aredispersible in plastics.

The Applicant wishes to indicate that there are a number of documentsrelating to the use of ethylene acrylic acid in a process of manufactureof calcium carbonate. On this subject, he wishes to emphasise:

-   -   firstly, that none of these documents seeks to resolve the same        technical problem as that of the present Application,    -   moreover, that none of these documents reveals the technical        solution of the present Application, which consists in the        process described above,    -   in addition, that nothing suggested in one of these documents,        or in possible combinations of one or more of these documents        mutually or with other documents, the process according to the        invention; and that on the contrary the teaching of these        documents could not lead the skilled man in the art to the        process forming the subject of the present invention.

These arguments will now be developed with regard to the content and theteaching revealed by each of the documents relating to the use ofethylene acrylic acid in the course of a process of manufacture ofcalcium carbonate.

The skilled man in the art is familiar with document U.S. Pat. No.6,808,809 which seeks to resolve the technical problem of manufacturinga mineral filler notably having good flowability; in relation thereto,this document does not in any way resolve the same technical problem asthat forming the subject of the present Application. The solution whichit proposes consists in introducing into a dryer an aqueous suspensionof mineral filler (such as calcium carbonate) having an average diameterof less than 15 μm, and an aqueous dispersion of a polymer (such asnotably ethylene acrylic acid). This document indicates that thesuspension of mineral filler may have a dry extract of between 10% and90% of the total weight of the said suspension; however, only example 1produced in the case of aluminium trihydroxide reveals a dry extractvalue, equal only to 55%. Nothing is, moreover, indicated concerning theviscosity of the suspensions obtained, nor concerning the possibility ofreducing the quantity of agglomerates of mineral matter. The Applicantstresses that in no case does this document reveal the use of ethyleneacrylic acid in the form of salts, which therefore constitutes anelement of distinction with the present invention. Finally, nothingsuggests to the skilled man in the art that he should attach particularimportance to the use of a dispersing agent in this document, and allthe more so to the use of a dispersing agent before the use of ethyleneacrylic acid in the form of salts; similarly, nothing suggests in thisdocument—centred around a drying process—a process according to theinvention which offers the possibility of treating a calcium carbonateboth during a grinding stage and a blending and concentration stage, inthe presence of at least one salt of ethylene acrylic acid, and of adispersing agent or grinding aid agent used before the stage oftreatment of calcium carbonate.

The skilled man in the art is also familiar with document WO 93/11183which seeks to resolve the technical problem of improving the dispersionof inorganic particles in different materials, such as paints,adhesives, putties, or again binders for non-woven materials; this istherefore a technical problem different to the one resolved by thepresent Application, since it does not address notably the question ofmanufacturing suspensions of mineral matter having a high dry extract.The described solution consists of a process of preparation of a stableaqueous dispersion, by the blending of an aqueous suspension ofinorganic particles (such as calcium carbonate) and of an aqueoussuspension of polymeric latex particles, after having adjusted theirzeta potentials. The ethylene acrylic acid is described as one of thepolymers which can be used, without it ever been exemplified, andwithout it ever being particularly distinguished among all the usablepolymers. In addition, the examples demonstrate that the resultingsuspensions have low dry extracts, always less than 60% by dry weight ofmineral particles relative to the total weight of the said suspensions.A fundamental element of distinction with the present invention is thatthis document never mentions the presence of salts of ethylene acrylicacid. Finally, nothing suggests to the skilled man in the art that heshould attach particular importance to the use of a dispersing agent inthis document, and all the more so to the use of a dispersing agentbefore the use of ethylene acrylic acid in the form of salts; similarly,nothing suggests in this document—centred around a blending process—aprocess according to the invention which offers the possibility oftreating a calcium carbonate both during a grinding stage and a blendingand concentration stage, in the presence of at least one salt ofethylene acrylic acid, and of a dispersing agent or grinding aid agentused before the stage of treatment of calcium carbonate.

The skilled man in the art is also familiar with document WO 97/13815which seeks to resolve the technical problem of manufacturing powderscompatible with plastics (but also paints and paper), of preventing thecoalescence of the particles which constitute such powders, of makingthe surface of the calcium carbonate hydrophobic; as such, this documentresolves only partially the problem forming the subject of the presentApplication. Indeed, the solution which it proposes does not enableaqueous suspensions of calcium carbonate to be obtained with a dryextract greater than 65% relative to the total weight of the saidsuspensions, as is notably demonstrated by the results of table 2 onpage 29. In addition, the proposed solution consists in dissolving,initially, a polymer (such as ethylene acrylic acid) in a mediumcontaining carboxylic acid, and then in bringing the product obtainedinto contact with calcium carbonate in such a way as to cause it toprecipitate on the latter: this stage of the solution constitutes afundamental element of differentiation with the present invention. Inaddition, this stage of dissolution, when it uses long-chain carboxylicacids, will lead to the same problems as those resulting from the use ofstearic acid, namely the need for an additional stage ofdisagglomeration and/or addition of additional additives of calciumcarbonate particles. This same stage of dissolution, when it usescarboxylic acids with shorter chains, will lead to the flocculation ofthe calcium carbonate particles, and will not therefore enable aqueoussuspensions with a high dry extract, and notably greater than 65% of thetotal weight of the said suspensions, to be obtained. These carboxylicacids with shorter chains can also destroy the calcium carbonateparticles, and even generate carbon dioxide. Finally, these short-chaincarboxylic acids can reduce the resistivity and increase theconductivity of the plastics in which the calcium carbonates accordingto the invention are finally used. Finally, nothing suggests to theskilled man in the art that he should attach particular importance tothe use of a dispersing agent in this document, and all the more so tothe use of a dispersing agent before the use of ethylene acrylic acid inthe form of salts; similarly, nothing suggests in this document—centredaround a blending process—a process according to the invention whichoffers the possibility of treating a calcium carbonate both during agrinding stage and a blending and concentration stage, in the presenceof at least one salt of ethylene acrylic acid, and of a dispersing agentor grinding aid agent used before the stage of treatment of calciumcarbonate.

The skilled man in the art is also familiar with document WO 02/96982which seeks to resolve the technical problem of manufacturing aorganic-inorganic nano-composite material, whilst strengthening withinthis said material the compatibility between the organic particles andthe inorganic particles; as such, this document does not resolve thesame technical problem as that forming the subject of the presentApplication. The solution which it proposes consists in forming a blendbetween a mineral particle (such as calcium carbonate) and a polymersolution (such as, for example, one with an ethylene acrylic acid base)in the presence of solvents, in evaporating the solvents, and inblending the product obtained with a polymer resin. This document givesno indication concerning the dry extracts of the blends of mineralparticles and polymers. Furthermore, it has the drawback of usingsolvents (such as notably THF and ethanol), the presence of which isundesirable for the skilled man in the art, notably because they willengender a high rate of volatile organic carbon (VOC) in the atmosphere.Finally, this process is different from that forming the subject of thepresent invention, since it does not mention the presence of adispersing agent. Finally, nothing suggests in this document—which iscentred around a blending process—a process according to the inventionwhich offers the possibility of treating calcium carbonate both during agrinding stage and during a blending or concentration stage, in thepresence of at least one salt of ethylene acrylic acid, and onedispersing agent or grinding aid agent used before the stage oftreatment of calcium carbonate.

The skilled man in the art is also familiar with document U.S. Pat. No.5,449,402 which seeks to resolve the technical problem of bindingirreversibly a mineral filler and an organic modifier, which are thenused in the composition of aqueous linings, the opacity and brightnessof which are improved; as such, this document absolutely does notresolve the same technical problem as the one forming the subject of thepresent Application. The solution which it proposes consists inmanufacturing a pigment from calcium carbonate particles in theflocculated state and from an anionic modifying agent (such as polymers,and notably ethylene acrylic acid), in which the calcium carbonate andthe modifying agent are then bound to one another by electrostaticlinks. The general teaching this document is that, in order to treat acalcium carbonate notably with a solution of ethylene acrylic acid, itis preferable to have initially one pigment in a flocculated form(column 4, lines 39 to 62), and not a dispersed pigment (as indicatedexplicitly on line 50 of column 4), where this dispersed state isdefined as resulting from the addition of an agent having led to areduction of the viscosity or to a reduction of the sizes of theparticles (column 1, lines 15 to 25). A dispersing agent such as sodiumpolyacrylate can subsequently be added after the introduction of thesolution of ethylene acrylic acid (column 4, lines 63 to 65).Consequently, the skilled man in the art is strongly encouraged not touse a dispersing agent before the treatment of the calcium carbonate bya solution of ethylene acrylic acid. This dispersed state, as defined indocument U.S. Pat. No. 5,449,402 as resulting from the addition of anagent leading to a reduction of viscosity or to a reduction of the sizeof the particles, is therefore undesired in this document; however, itforms part of one of the fundamental characteristics of the presentinvention. Finally, the Applicant was able to observe that, in asurprising manner since it was completely contrary to the teaching ofthe prior art, the introduction of a dispersing agent necessarily beforeor during the addition of salts of ethylene acrylic acid to treat thecalcium carbonate, enables by this means the calcium carbonate to bemade at once partially organophilic and partially hydrophilic, withoutusing stearic acid, enables aqueous suspensions to be obtained with ahigh dry extract and a satisfactory rheology and without agglomerates,and enables the skilled man in the art to be given a very flexibleprocess, since the ethylene acrylic acid can be used either during astage of grinding, or of blending, or of concentration.

Therefore, none of the documents available to the skilled man in the artconcerning the use of ethylene acrylic acid concerns the same technicalproblem as the one resolved by the present Application.

Similarly, none of them reveals the technical solution forming thesubject of the present Application.

Finally, none of them, nor mutual combinations of them, nor combinationswith other documents, suggests the technical solution forming thesubject of the present Application.

One of the merits of the Applicant notably resides in the fact that hewas able to observe that the following particular choices:

-   -   the use of salts of ethylene acrylic acid to treat a natural        and/or precipitated calcium carbonate,    -   the addition of a dispersing agent and/or grinding aid agent        before and/or during the stage of treatment of the calcium        carbonate by salts of ethylene acrylic acid (which is contrary        to the teaching of the state of the technique),        -   enable in a surprising manner the development of a process:    -   which avoids the drawbacks relating to the use of stearic acid        (a stage of disagglomeration and of addition of additional        additives), which represents a financial gain,    -   which enables aqueous suspensions of mineral matter with high        dry extract to be obtained (notably greater than 65%) with a        satisfactory rheology, and without the presence of agglomerates        which would create residues on the filtration screens,        representing a technical and economic interest,    -   which enables the skilled man in the art to be given a process        in which he can treat calcium carbonate both during a stage of        grinding and of blending or concentration in an aqueous medium,        which represents very great flexibility.

In addition, this process enables a natural and/or precipitated calciumcarbonate to be obtained which is at once partially organophilic andpartially hydrophilic, which is very surprising.

It is notably very surprising that, if the salts of ethylene acrylicacid are added during or after the addition of dispersing agent, thesesalts do not influence in a negative fashion the rheological propertiesof the dispersions obtained: indeed, one succeeds surprisingly, usingthe process according to the invention, in obtaining high dry extracts(notably greater than 65%) with satisfactory rheological properties andwithout the formation of agglomerates.

At the same time, it is very surprising that the dispersing agent (whichis added before or during the introduction of the ethylene acrylic acidsalts) does not prevent the interaction between the said salts and thesurface of the calcium carbonate in order to make it organophilic:indeed, one succeeds surprisingly, using the process according to theinvention, in manufacturing calcium carbonate particles which aredispersible in plastics.

Finally, the Applicant wishes to indicate that he is familiar withFrench patent Application No. 04 07806, which has been filed but not yetpublished, and which therefore intervenes only as a novelty in order toassess the patentability of the present Application.

In this respect, French patent Application No. 04 07806 describes aprocess of preparation of self-binding pigmentary particles, which areeither dry or in aqueous suspension or dispersion, including thefollowing stages:

-   -   a) forming one or more aqueous suspensions of at least one        inorganic matter and introducing it or them into a mill with a        view to stage c),    -   b) forming or taking one or more aqueous solutions or        suspensions or emulsions of at least one binder and introducing        it or them into a mill with a view to stage c),    -   c) co-grinding the aqueous suspension or suspensions obtained in        stage a) with the aqueous solutions or suspensions or emulsions        obtained in stage b) so as to obtain an aqueous suspension of        self-binding pigmentary particles,    -   d) possibly co-grinding the aqueous suspension obtained in        stage c) with one or more aqueous solutions or suspensions or        emulsions of at least one binder,    -   e) possibly drying the aqueous suspension obtained in stage c)        or in stage d).

This process, as indicated in French patent Application No. 04 07806,spares the skilled man in the art from using a third constituent duringthe preparation of the aqueous suspensions containing the inorganicmatter and the binders, and during the co-grinding stage: this thereforeconstitutes a fundamental difference with the present invention, whichnecessarily uses a dispersing agent and/or grinding aid agent before orduring the stage of treatment of mineral matter by ethylene acrylicacid.

Therefore, a first object of the invention lies in a process ofpreparation of at least one mineral matter and/or at least one pigment,including a natural and/or precipitated calcium carbonate,preferentially natural, made at once partially organophilic andpartially hydrophilic, and including the stages of:

-   -   a) supplying at least one mineral matter and/or one pigment        including natural and/or precipitated calcium carbonate,        preferentially natural, in a dry form or in the form of an        aqueous dispersion and/or suspension,    -   b) possibly dry grinding and/or grinding in an aqueous medium        the mineral matter and/or the pigment resulting from stage a),    -   c) treating the mineral matter and/or the pigment resulting from        stage a) and/or from stage b),    -   d) possibly drying the mineral matter and/or the pigment        resulting from stage a) and/or b) and/or c),        characterised in that:    -   treatment stage c) corresponds to a stage of blending in an        aqueous medium and/or of grinding in an aqueous medium, and/or        of concentration in an aqueous medium, of the mineral matter        and/or the pigment obtained from stage a) and/or from stage b),        in the presence of at least one salt of ethylene acrylic acid,    -   a dispersing agent and/or grinding aid agent is introduced        before and/or during the treatment stage c).

The Applicant recalls that, according to this process, the mineralmatter and/or the pigment including at least one natural calciumcarbonate, when it is present in the form of an aqueous dispersion orsuspension, is not in the flocculated state, unlike that which isclaimed by document U.S. Pat. No. 5,449,402.

The process according to the invention is also characterised in that theethylene acrylic acid salt is a salt which is soluble in aqueous media.

The process according to the invention is also characterised in that thecarboxylic groupings of the ethylene acrylic acid salt are partially ortotally dissociated from their acid proton.

The process according to the invention is also characterised in that, inthe ethylene acrylic acid salt, the mass ratio of ethylene monomer toacrylic acid monomer is between 10:90 and 30:70, and is preferentiallyequal to 20:80.

The process according to the invention is also characterised in that theethylene acrylic acid salt has a melt index of between 50 g/10 minutesand 1,500 g/10 minutes, preferentially between 200 g/10 minutes and 300g/10 minutes when the ethylene acrylic acid salt is totally neutralised,and preferentially between 1,000 g/10 minutes and 1,400 g/10 minuteswhen the ethylene acrylic acid salt is neutralised at a rate of 70 to99% (as a proportion of the carboxylic sites of the ethylene acrylicacid), measured according to norm ASTM1238 125° C./2.16 kg.

The process according to the invention is also characterised in that thecarboxylic groupings of the said ethylene acrylic acid salts areentirely neutralised or neutralised at a rate of 70 to 99% relative tothe total number of the carboxylic sites of the ethylene acrylic acid,with at least one neutralisation agent.

The process according to the invention is also characterised in that thesaid neutralisation agent includes at least one monovalent cation.

The process according to the invention is also characterised in that thesaid monovalent cation includes one or more alkali ions and/or one ormore amines and/or ammonia.

The process according to the invention is also characterised in that thesaid alkaline monovalent ion includes a sodium ion.

The process according to the invention is also characterised in that thesaid amine includes a primary amine.

The process according to the invention is also characterised in that thesaid amine includes an alkanolamine, including at least one ethanoland/or propanol grouping, and in that the said alkanolamine is thenpreferentially chosen from among 2-amino-2-methyl-1-propanol and/ordimethylethanolamine, and in that it is very preferentially2-amino-2-methyl-1-propanol.

The process according to the invention is also characterised in that aquantity of 2-amino-2-methyl-1-propanol is used, so as to contribute aproportion of monovalent cation of between 75 and 125% of the carboxylicgroupings of the ethylene acrylic acid, and preferentially so as tocontribute a proportion of monovalent cation equal to 100% of thecarboxylic groupings of the ethylene acrylic acid.

The process according to the invention is also characterised in that aquantity of dimethyl ethanolamine is used, so as to contribute aproportion of monovalent cation of between 75 and 125% of the carboxylicgroupings of the ethylene acrylic acid, and preferentially so as tocontribute a proportion of monovalent cation equal to 100% of thecarboxylic groupings of the ethylene acrylic acid.

The process according to the invention is also characterised in that thesaid ethylene acrylic acid has a viscosity of 3,000 to 25,000 mPa·s,15,000 to 100,000 mPa·s, and 50,000 to 400,000 mPa·s at respectivetemperatures of 200° C., 170° C. and 140° C.

In a particular embodiment, the process according to the invention ischaracterised in that the said ethylene acrylic acid has a viscosity of3,000 to 7,000 mPa·s, 15,000 to 20,000 mPa·s, and 50,000 to 100,000mPa·s at respective temperatures of 200° C., 170° C. and 140° C.

In another particular embodiment, the process according to the inventionis characterised in that the said ethylene acrylic acid has a viscosityof 15,000 to 25,000 mPa·s, 50,000 to 100,000 mPa·s, and 300,000 to400,000 mPa·s at respective temperatures of 200° C., 170° C. and 140° C.

The process according to the invention is also characterised in that themineral matter and/or the pigment includes, in addition to calciumcarbonate, also at least one other mineral matter and/or pigment chosenfrom among the dolomites, the bentonites, kaolin, talc, cement, gypsum,lime, magnesia, titanium dioxide, satin white, aluminium trioxide, oragain aluminium trihydroxide, the silicas, mica and a blend of thesefillers one with another, such as talc-calcium carbonate blends, calciumcarbonate-kaolin blends, or again blends of calcium carbonate withaluminium trihydroxide or aluminium trioxide, or again blends withsynthetic or natural fibres, or again mineral costructures such astalc-calcium carbonate costructures or talc-titanium dioxidecostructures, or their blends, and in that this other mineral matter ispreferentially kaolin.

The process according to the invention is also characterised in that thequantity by dry weight of calcium carbonate is greater than or equal to70% of the total dry weight of pigments and/or of mineral matter.

The process according to the invention is also characterised in that,during stage a) and when the mineral matter and/or the pigment ispresent in the form of an aqueous dispersion and/or suspension, theconcentration by dry weight of pigment and/or mineral matter is greaterthan 60%, preferentially 65%, very preferentially greater than 70%, mostpreferentially is between 74% and 78% of the total weight of the saiddispersion and/or suspension, or in that the concentration by dry weightof pigment and/or mineral matter is less than 30%, preferentiallybetween 18 and 22%, of the total weight of the said dispersion and/orsuspension, and in that the said dispersion and/or suspension is asuspension containing no dispersing agent.

The Applicant stresses that these limitations apply to stage a), and notto the aqueous dispersion and/or suspension obtained after stage c), thedry extract of which it is necessarily sought to increase, which formspart of one of the aspects of the technical problem resolved by thepresent Application.

The process according to the invention is also characterised in that thegrinding stage b) is undertaken continuously or discontinuously, andpreferentially continuously.

The process according to the invention is also characterised in that thegrinding stage b) is undertaken in the presence of oxide-based and/orzirconium silicate-based grinding balls, possibly stabilised with acerium and/or yttrium oxide.

In the embodiment according to which the grinding stage b) is drygrinding, the process according to the invention is also characterisedin that the dry grinding stage leads to the production of mineral matterand/or pigments having an average diameter of less than 50 μm,preferentially less than 15 μm, very preferentially less than 5 μm, andeven more preferentially in that the average diameter is between 1.3 and1.7 μm, as measured using a Sedigraph™ 5100 device sold by the companyMICROMERITICS™.

In the variant according to which the grinding stage b) is a grinding inan aqueous medium, the process according to the invention is alsocharacterised in that this grinding stage in an aqueous medium leads tothe production of mineral matter and/or pigments having a proportion ofparticles with a diameter of less than 2 μm greater than 60% (asmeasured by a Sedigraph™ 5100 device sold by the companyMICROMERITICS™), or a proportion of particles with a diameter of lessthan 2 μm greater than 90% (as measured by a Sedigraph™ 5100 device soldby the company MICROMERITICS™), or a proportion of particles with adiameter of less than 2 μm greater than 99% (as measured by a Sedigraph™5100 device sold by the company MICROMERITICS™).

The process according to the invention is also characterised in thattreatment stage c) leads to an aqueous dispersion and/or suspension ofwhich the percentage by dry weight of mineral matter and/or of pigmentsis greater than 65%, preferentially greater than 70%, verypreferentially greater than 75%, and most preferentially between 75 and78%, of the total weight of the said dispersion and/or suspension.

The process according to the invention is also characterised in thattreatment stage c) leads to an aqueous dispersion and/or suspension themineral matter and/or the pigments of which have an average diameter ofless than 50 μm, preferentially less than 15 μm, very preferentiallyless than 5 μm, and even more preferentially in that the averagediameter is between 0.3 and 1.7 μm, and most preferentially is between0.5 and 0.9 μm, as measured by a Sedigraph™ 5100 device sold by thecompany MICROMERITICS™.

The process according to the invention is also characterised in thattreatment stage c) leads to an aqueous dispersion and/or suspensionhaving a proportion of particles with a diameter of less than 2 μmgreater than 60% (as measured by a Sedigraph™ 5100 device sold by thecompany MICROMERITICS™), or a proportion of particles with a diameter ofless than 2 μm greater than 90% (as measured by a Sedigraph™ 5100 devicesold by the company MICROMERITICS™), or a proportion of particles with adiameter of less than 2 μm greater than 99% (as measured by a Sedigraph™5100 device sold by the company MICROMERITICS™).

The process according to the invention is also characterised in thattreatment stage c) leads to an aqueous dispersion and/or suspensionhaving a Brookfield™ viscosity measured at 100 revolutions/minute(measured at 25° C., with mobile No. 3, and with device DVII+ in a1-liter container) of less than 1,000 mPa·s, preferentially less than700 mPa·s, very preferentially less than 500 mPa·s, and even morepreferentially in that this viscosity is between 100 and 300 mPa·s.

The process according to the invention is also characterised in thattreatment stage c) leads to an aqueous dispersion and/or suspensionhaving a screen residue greater than 45 μm of less than 100 ppm,preferentially of less than 70 ppm, more preferentially of less than 60ppm, and most preferentially of less than 50 ppm.

The process according to the invention is also characterised in thatstage c) is preferentially a stage of grinding in an aqueous medium.

The process according to the invention is also characterised in thatdrying stage d) is undertaken preferentially after treatment stage c).

The process according to the invention is also characterised in that thedrying is undertaken by a dryer-atomiser.

The process according to the invention is also characterised in that thedispersing agent and/or grinding aid agent in an aqueous medium,introduced during or before stage c), is a homopolymer of acrylic acidand/or a copolymer of acrylic acid with another water-soluble monomerchosen from among methacrylic acid, maleic acid, itaconic acid, crotonicacid, fumaric acid, isocrotonic acid, aconitic acid, mesaconic acid,sinapic acid, undecylenic acid, angelic acid, canellic acid and/or2-acrylamido 2-methyl propane sulfonic acid in acid form or partiallyneutralised, or again from among acrylamide, methylacrylamide, theesters of the acrylic or methacrylic acids such as acrylate phosphate orethylene methacrylate or propylene glycol, or again from amongvinylpyrrolidone, vinylcaprolactame, vinyl acetate, sodium styrenesulfonate, allylamine and its derivatives, and preferentially in thatthe dispersing agent and/or grinding aid agent is one chosen from amongthe copolymers of acrylic acid with acrylamide or maleic acid.

The process according to the invention is also characterised in that thedry grinding agent used in stage b) of grinding, when the latter is drygrinding, is chosen from among the glycol-based compounds, andpreferentially from among ethylene glycol, diethylene glycol ormonopropylene glycol, and in that it is preferentially a monopropyleneglycol of molecular weight of between 200 and 1,000 g/mole.

The process according to the invention is also characterised in that thetotal proportion of ethylene acrylic acid is between 0.1 and 10%,preferentially between 0.2 and 2%, and is very preferentially equal to0.5 to 1% of the dry weight of pigments and/or of mineral matter.

The process according to the invention is also characterised in that thetotal proportion of dispersing agent and/or grinding aid agent isbetween 0.1 and 2%, preferentially between 0.2 and 1.5%, and is verypreferentially between 0.3 and 0.6% of the dry weight of pigments and/orof mineral matter.

The process according to the invention is also characterised in that thequantity by weight of ethylene acrylic acid is approximately equal tothe quantity by weight of dispersing agent and/or grinding aid agent,when the ethylene acrylic acid is neutralised with2-amino-2-methyl-1-propanol.

The process according to the invention is also characterised in that thequantity by weight of ethylene acrylic acid is approximately equal tohalf the quantity by weight of dispersing agent and/or grinding aidagent, when the ethylene acrylic acid is neutralised with sodium.

Another object of the invention lies in aqueous suspensions and/ordispersions of pigments and/or of mineral matter, characterised in thatthey are obtained by the process according to the invention.

Another object of the invention lies in the aqueous suspensions and/ordispersions of pigments and/or of mineral matter characterised in thatthey include calcium carbonate, at least one salt of ethylene acrylicacid, and in that they have a dry extract greater than 65%,preferentially greater than 70%, very preferentially greater than 75%,and even more preferentially between 75 and 78%, of their total weight.

These aqueous dispersions and/or suspensions are also characterised inthat the mineral matter and/or the pigments have an average diameter ofless than 50 μm, preferentially less than 15 μm, very preferentiallyless than 5 μm, and even more preferentially in that the averagediameter is between 0.3 and 1.7 μm, and even more preferentially isbetween 0.5 and 0.9 μm, as measured by a Sedigraph™ 5100 device sold bythe company MICROMERITICS™.

These aqueous dispersions and/or suspensions are also characterised inthat they have a proportion of particles with a diameter of less than 2μm greater than 60% (as measured by a Sedigraph™ 5100 device sold by thecompany MICROMERITICS™), or a proportion of particles with a diameter ofless than 2 μm greater than 90% (as measured by a Sedigraph™ 5100 devicesold by the company MICROMERITICS™), or a proportion of particles with adiameter of less than 2 μm greater than 99% (as measured by a Sedigraph™5100 device sold by the company MICROMERITICS™).

These aqueous dispersions and/or suspensions are also characterised inthat they have a Brookfield™ viscosity measured at 100revolutions/minute (at 25° C., with mobile No. 3, with the DVII+ device,in a 1-liter container) of less than 1,000 mPa·s, preferentially lessthan 700 mPa·s, very preferentially less than 500 mPa·s, and even morepreferentially in that this viscosity is between 100 and 300 mPa·s.

These aqueous dispersions and/or suspensions are also characterised inthat they have a screen residue greater than 45 μm, of less than 100ppm, preferentially of less than 70 ppm, more preferentially of lessthan 60 ppm, and most preferentially of less than 50 ppm.

These aqueous dispersions and/or suspensions are also characterised inthat the ethylene acrylic acid salt is a salt which is soluble inaqueous media.

These aqueous dispersions and/or suspensions are also characterised inthat the carboxylic groupings of the ethylene acrylic acid salt arepartially or totally dissociated from their acid proton.

These aqueous dispersions and/or suspensions are also characterised inthat, in the ethylene acrylic acid salt, the mass ratio of ethylenemonomer to acrylic acid monomer is between 10:90 and 30:70, and ispreferentially equal to 20:80.

These aqueous dispersions and/or suspensions are also characterised inthat the ethylene acrylic acid salt has a melt index of between 50 g/10minutes and 1,500 g/10 minutes, preferentially between 200 g/10 minutesand 300 g/10 minutes when the ethylene acrylic acid salt is totallyneutralised, and preferentially between 1,000 g/10 minutes and 1,400g/10 minutes when the ethylene acrylic acid salt is neutralised at arate of 70 to 99% (as a proportion of the carboxylic sites), measuredaccording to norm ASTM1238 125° C./2.16 kg.

These aqueous dispersions and/or suspensions are also characterised inthat the carboxylic groupings of the said ethylene acrylic acid saltsare entirely neutralised or neutralised at a rate of 70 to 99% relativeto the total number of the carboxylic sites of the ethylene acrylicacid, with at least one neutralisation agent.

These aqueous dispersions and/or suspensions are also characterised inthat the said neutralisation agent includes at least one monovalentcation.

These aqueous dispersions and/or suspensions are also characterised inthat the said monovalent cation includes one or more alkali ions and/orone or more amines and/or ammonia.

These aqueous dispersions and/or suspensions are also characterised inthat the said neutralisation alkali includes at least one sodium ion.

These aqueous dispersions and/or suspensions are also characterised inthat the said amine includes a primary amine.

These aqueous dispersions and/or suspensions are also characterised inthat the said amine includes an alkanolamine, including at least oneethanol and/or propanol grouping, and in that the said alkanolamine isthen preferentially chosen from among 2-amino-2-methyl-1-propanol and/ordimethylethanolamine, and in that it is very preferentially2-amino-2-methyl-1-propanol.

These aqueous dispersions and/or suspensions are also characterised inthat a quantity of 2-amino-2-methyl-1-propanol is used, so as tocontribute a proportion of monovalent cation of between 75 and 125% ofthe carboxylic groupings of the ethylene acrylic acid, andpreferentially so as to contribute a proportion of monovalent cationequal to 100% of the carboxylic groupings of the ethylene acrylic acid.

These aqueous dispersions and/or suspensions are also characterised inthat a quantity of dimethyl ethanolamine is used, so as to contribute aproportion of monovalent cation of between 75 and 125% of the carboxylicgroupings of the ethylene acrylic acid, and preferentially so as tocontribute a proportion of monovalent cation equal to 100% of thecarboxylic groupings of the ethylene acrylic acid.

These aqueous dispersions and/or suspensions are also characterised inthat the said ethylene acrylic acid has a viscosity of 3,000 to 25,000mPa·s, 15,000 to 100,000 mPa·s, and 50,000 to 400,000 mPa·s atrespective temperatures of 200° C., 170° C. and 140° C.

These aqueous dispersions and/or suspensions are also characterised inthat the said ethylene acrylic acid has a viscosity of 3,000 to 7,000mPa·s, 15,000 to 20,000 mPa·s, and 50,000 to 100,000 mPa·s at respectivetemperatures of 200° C., 170° C. and 140° C.

These aqueous dispersions and/or suspensions are also characterised inthat the said ethylene acrylic acid has a viscosity of 15,000 to 25,000mPa·s, 50,000 to 100,000 mPa·s, and 300,000 to 400,000 mPa·s atrespective temperatures of 200° C., 170° C. and 140° C.

Another object of the invention lies in the dry pigments obtained by theprocess according to the invention (i.e. after the drying stage d)).

These dry pigments are also characterised in that they contain calciumcarbonate, at least one salt of ethylene acrylic acid, of which thecalcium carbonate particles have an average diameter of less than 50 μm,preferentially less than 15 μm, very preferentially less than 5 μm, andeven more preferentially in that the average diameter is between 0.3 and1.7 μm, and even more preferentially is between 0.5 and 0.9 μm (asmeasured by a Sedigraph™ 5100 device sold by the companyMICROMERITICS™).

These dry pigments are also characterised in that the calcium carbonateparticles have a proportion of particles with a diameter of less than 2μm greater than 60% (as measured by a Sedigraph™ 5100 device sold by thecompany MICROMERITICS™), or a proportion of particles with a diameter ofless than 2 μm greater than 90% (as measured by a Sedigraph™ 5100 devicesold by the company MICROMERITICS™), or a proportion of particles with adiameter of less than 2 μm greater than 99% (as measured by a Sedigraph™5100 device sold by the company MICROMERITICS™).

Another object of the invention lies in the use of the aqueousdispersions and suspensions according to the invention, together withdry pigments according to the invention, in the fields of paper, plasticand paints, notably in paper and plastic mass, and in paper and plasticcoatings.

EXAMPLES Example 1

This example illustrates the process according to the invention, inwhich a natural calcium carbonate is treated by a salt of ethyleneacrylic acid during a stage of grinding in an aqueous medium, where adispersing agent is introduced during the said grinding stage.

In relation thereto, this example starts by describing the copolymers ofthe ethylene acrylic acid used, followed by the manufacture of certainof their salts.

Note: all the granulometric characteristics of the calcium carbonatesuspensions were measured using a device of the Sedigraph™ 5100 typesold by the company MICROMERITICS™.

Copolymer of Ethylene Acrylic Acid a)

This copolymer designates a copolymer of ethylene acrylic acid comprised20% by weight of acrylic acid and 80% by weight of ethylene.

Copolymer of Ethylene Acrylic Acid b)

This copolymer designates a copolymer of ethylene acrylic acid comprised20% by weight of acrylic acid and 80% by weight of ethylene.

This copolymer has a melt index of 1,300 g/10 minutes, measuredaccording to norm ASTM 1238 125° C./2.16 kg.

It is well known that a high melt index corresponds to a low molecularweight.

Copolymer of Ethylene Acrylic Acid c)

This copolymer designates a copolymer of ethylene acrylic acid comprised20% by weight of acrylic acid and 80% by weight of ethylene.

This copolymer has a melt index of 300 g/10 minutes, measured accordingto norm ASTM 1238 125° C./2.16 kg.

The viscosities (mPa·s) of these different copolymers are indicated intable 1, as a function of temperature. These rheological properties givea basis of comparison of the molecular weights of these copolymers: alow viscosity indicates a low molecular weight.

These viscosity values were measured at the temperatures indicated belowwith a rheometer sold under the name MCR 300 by the company PHYSICA™with the following conditions: cone-plane rheometer CP50-1, with aconstant shearing rate equal to 5 s⁻¹, in a temperature interval rangingfrom 200° C. to 120° C., in steps of 0.0833° C./s.

TABLE 1 viscosities of the different copolymers of ethylene acrylic acidas a function of temperature Viscosity Viscosity Viscosity Temperature(mPa · s) of (mPa · s) of (mPa · s) of (° C.) copolymer a) copolymer b)copolymer c) 200 24,300 5,200 21,700 190 37,300 7,850 33,400 180 56,30011,600 50,100 170 88,300 17,300 74,500 160 138,000 25,100 109,000 150225,000 43,000 190,000 140 367,000 72,900 326,000 130 628,000 127,000568,000Solution of Ethylene Acrylic Acid No. 1

500 grams of copolymer a) are added into 2.5 liters of deionised waterin a 10-liter reactor of the ESCO type.

While stirring, 123.7 grams of 2-amino-2-methyl-1-propanol (so as toneutralise 100% the carboxylic acid sites of the ethylene acrylic acid)were added, and the blend was heated for one hour at 98° C.

A clear and limpid solution is thus obtained.

Solution of Ethylene Acrylic Acid No. 2

500 grams of copolymer a) are added into 2.5 liters of deionised waterin a 10-liter reactor of the ESCO type.

While stirring, 130.2 grams of di-methyl ethanolamine (so as toneutralise 100% the carboxylic acid sites of the ethylene acrylic acid)were added, and the blend was heated for one hour at 98° C.

A clear and limpid solution is thus obtained.

Solution of Ethylene Acrylic Acid No. 3

500 grams of copolymer b) are added into 5 liters of deionised water ina 10-liter reactor of the ESCO type.

While stirring, 38.8 grams of soda (so as to neutralise 75% thecarboxylic acid sites of the ethylene acrylic acid) were added, and theblend was heated for one hour at 98° C.

A clear and limpid solution is thus obtained.

Solution of ethylene acrylic acid No. 4

500 grams of copolymer b) are added into 5 liters of deionised water ina 10-liter reactor of the ESCO type.

While stirring, 55.4 grams of soda (so as to neutralise all thecarboxylic acid sites of the ethylene acrylic acid) were added, and theblend was heated for one hour at 98° C.

A clear and limpid solution is thus obtained.

Solution of Ethylene Acrylic Acid No. 5

500 grams of copolymer c) are added into 5 liters of deionised water ina 10-liter reactor of the ESCO type.

While stirring, 54.1 grams of soda (so as to neutralise all thecarboxylic acid sites of the ethylene acrylic acid) were added, and theblend was heated for one hour at 98° C.

A clear and limpid solution is thus obtained.

Solution of Ethylene Acrylic Acid No. 6

500 grams of copolymer b) are added into 2.5 liters of deionised waterin a 10-liter reactor of the ESCO type.

While stirring, 200 grams of ammonia (so as to neutralise 100% thecarboxylic acid sites of the ethylene acrylic acid) were added, and theblend was heated for one hour at 98° C.

A clear and limpid solution is thus obtained.

Test No. 1a

This test illustrates the prior art.

It uses a marble of Norway, the average diameter of the particles ofwhich is equal to 45 μm.

This marble was ground in an aqueous medium in a grinder of theDynomill™ type of 1.4 liters with 2,700 grams of zirconium dioxide-basedgrinding balls of diameter of between 0.6 and 1 mm, and in the presenceof 0.65% by dry weight of a homopolymer of acrylic acid neutralised bysodium and magnesium, and of molecular weight equal to 5,400 g/mole,relative to the dry weight of marble.

The grinding required 11 minutes/kg.

An aqueous suspension of marble is obtained the dry extract of which isequal to 75.5%, and the size of the particles of which is such that 90%by weight of them have a diameter of less than 2 μm.

The Brookfield™ viscosity measured at 25° C. and at 100revolutions/minute with mobile number 3 is 251 mPa·s.

This viscosity is measured on a DVII+ device, in a 1-liter container;this procedure will be used in the other tests.

The screen residue of greater than 45 μm was 40 ppm.

Test No. 1b

This test illustrates the prior art.

It uses a marble of Norway, the average diameter of the particles ofwhich is equal to 45 μm.

This marble was ground in an aqueous medium in a grinder of theDynomill™ type of 1.4 liters with 2,700 grams of zirconium dioxide-basedgrinding balls of diameter of between 0.6 and 1 mm, in the presence of1.0% by dry weight of the solution of ethylene acrylic acid No. 6.

An aqueous suspension of marble is obtained the dry extract of which isequal to 38.0%, and the size of the particles of which is such that 73%by weight of them have a diameter of less than 2 μm. It is impossible toincrease the dry extract without impairing the viscosity as indicatedbelow.

The Brookfield™ viscosity measured at 25° C. and at 100revolutions/minute with mobile number 3 is between 250 and 600 mPa·s.

Test No. 2

This test illustrates the invention.

It uses a marble of Norway, the average diameter of the particles ofwhich is equal to 45 μm.

This marble was ground in an aqueous medium in a grinder of theDynomill™ type of 1.4 liters with 2,700 grams of zirconium dioxide-basedgrinding balls of diameter of between 0.6 and 1 mm, and in the presenceof 0.67% by dry weight of a homopolymer of acrylic acid neutralised bysodium and magnesium, and of molecular weight equal to 5,400 g/mole,relative to the dry weight of marble, and in the presence of 0.5% by dryweight of the solution of ethylene acrylic acid No. 1.

An aqueous suspension of marble is obtained the dry extract of which isequal to 75.7%, and the size of the particles of which is such that 89%by weight of them have a diameter of less than 2 μm.

The Brookfield viscosity measured at 25° C. and at 100revolutions/minute with mobile number 3 is 150 mPa·s.

The screen residue of greater than 45 μm was 13 ppm.

Test No. 3

This test illustrates the invention.

It uses a marble of Norway, the average diameter of the particles ofwhich is equal to 45 μm.

This marble was ground in an aqueous medium in a grinder of theDynomill™ type of 1.4 liters with 2,700 grams of zirconium dioxide-basedgrinding balls of diameter of between 0.6 and 1 mm, and in the presenceof 1.04% by dry weight of a homopolymer of acrylic acid neutralised bysodium and magnesium, and of molecular weight equal to 5,400 g/mole,relative to the dry weight of marble, and in the presence of 0.5% by dryweight of the solution of ethylene acrylic acid No. 2.

The grinding required 11.3 minutes/kg.

An aqueous suspension of marble is obtained the dry extract of which isequal to 76.1%, and the size of the particles of which is such that 92%by weight of them have a diameter of less than 2 μm.

The Brookfield™ viscosity measured at 25° C. and at 100revolutions/minute with mobile number 3 is 160 mPa·s.

Test No. 4

This test illustrates the invention.

It uses a marble of Norway, the average diameter of the particles ofwhich is equal to 45 μm.

This marble was ground in an aqueous medium in a grinder of theDynomill™ type of 1.4 liters with 2,700 grams of zirconium dioxide-basedgrinding balls of diameter of between 0.6 and 1 mm, and in the presenceof 1.00% by dry weight of a homopolymer of acrylic acid neutralised bysodium and magnesium, and of molecular weight equal to 5,400 g/mole,relative to the dry weight of marble, and in the presence of 0.5% by dryweight of the solution of ethylene acrylic acid No. 3.

An aqueous suspension of marble is obtained the dry extract of which isequal to 74.1%, and the size of the particles of which is such that 90%by weight of them have a diameter of less than 2 μm.

The Brookfield™ viscosity measured at 25° C. and at 100revolutions/minute with mobile number 3 is 153 mPa·s.

The screen residue of greater than 45 μm was 59 ppm.

Test No. 5

This test illustrates the invention.

It uses a marble of Norway, the average diameter of the particles ofwhich is equal to 45 μm.

This marble was ground in an aqueous medium in a grinder of theDynomill™ type of 1.4 liters with 2,700 grams of zirconium dioxide-basedgrinding balls of diameter of between 0.6 and 1 mm, and in the presenceof 1.00% by dry weight of a homopolymer of acrylic acid neutralised bysodium and magnesium, and of molecular weight equal to 5,400 g/mole,relative to the dry weight of marble, and in the presence of 0.5% by dryweight of the solution of ethylene acrylic acid No. 4.

An aqueous suspension of marble is obtained the dry extract of which isequal to 77.0%, and the size of the particles of which is such that 91%by weight of them have a diameter of less than 2 μm.

The Brookfield™ viscosity measured at 25° C. and at 100revolutions/minute with mobile number 3 is 157 mPa·s.

Test No. 6

This test illustrates the invention.

It uses a marble of Norway, the average diameter of the particles ofwhich is equal to 45 μm.

This marble was ground in an aqueous medium in a grinder of theDynomill™ type of 1.4 liters with 2,700 grams of zirconium dioxide-basedgrinding balls of diameter of between 0.6 and 1 mm, and in the presenceof 1.00% by dry weight of a homopolymer of acrylic acid neutralised bysodium and magnesium, and of molecular weight equal to 5,400 g/mole,relative to the dry weight of marble, and in the presence of 0.5% by dryweight of the solution of ethylene acrylic acid No. 5.

An aqueous suspension of marble is obtained the dry extract of which isequal to 76.9%, and the size of the particles of which is such that 89%by weight of them have a diameter of less than 2 μm.

The Brookfield™ viscosity measured at 25° C. and at 100revolutions/minute with mobile number 3 is 187 mPa·s.

The results demonstrate that the process according to the inventionleads to suspensions of calcium carbonate treated with a salt ofethylene acrylic acid and a dispersing agent, having a high dry extract,and notably greater than 75%.

In addition, this dry extract is greater than that obtained in theprocess according to the prior art, and the Brookfield™ viscositiesmeasured at 25° C. and at 100 revolutions/minute are lower than thoseobtained in the case of the prior art.

In addition, it was demonstrated that the grinding is as efficient withor without ethylene acrylic acid, by a comparison between tests No. 1 aand 3.

In addition, no example according to the invention presented a problemof creation of foam in the calcium carbonate suspension.

Moreover, it was observed that the screen residues obtained in the caseof the invention were completely negligible.

Test No. 7

This test illustrates the prior art.

A high-density polyethylene of the company BASELL™ POLYOLEFINS soldunder the name Hostalen™ GM 9240 HT was introduced into a roll mill soldunder the name Walzwerk 150×400 of the company DR. COLLIN.

After this, plates 2 and 4 mm in thickness were formed in a “TestingPlaten Presses Type P” P300-P press of the company DR. COLLIN.

Test No. 8

This test illustrates the invention.

The suspension of test No. 5 was dried with an MSD™ 100 pulveriser ofthe company NIRO™. A dry treated marble is obtained, the size of theparticles of which is such that 88% by weight of them have a diameter ofless than 2 μm.

The treated and dry marble was then blended at 180° C. with ahigh-density polyethylene of the company BASELL™ POLYOLEFINS sold underthe name Hostalen™ GM 9240 HT in a roll mill sold under the nameWalzwerk 150×400 of the company DR. COLLIN. The composition of the blendhas equal masses of the treated product and of the high-densitypolyethylene.

After this, plates 2 and 4 mm in thickness were formed in a “TestingPlaten Presses Type P” P300-P press of the company DR. COLLIN.

The traction resistances of the plates formed for tests No. 7 and 8 areequal respectively to 23.9 N/mm² and 24.2 N/mm² according to norm DIN53455.

It is observed that the replacement of part of the polyethylene by thepigment according to the invention does not reduce the tractionresistance.

The invention claimed is:
 1. An aqueous suspension or dispersion ofmineral matter comprising calcium carbonate and at least one salt ofethylene acrylic acid, wherein the carboxylic groupings of the ethyleneacrylic acid salt are entirely neutralized or neutralized at a rate of70 to 99% relative to the total number of the carboxylic sites of theethylene acrylic acid, with at least one neutralization agent thatincludes one or more amines, wherein the suspension or dispersion has adry weight of greater than 65% based on the total weight of the aqueoussuspension or dispersion of mineral matter, wherein the ethylene acrylicacid salt has a mass ratio of ethylene monomer to acrylic acid monomerof between 10:90 and 30:70, wherein the ethylene acrylic acid salt has amelt index of between 50 g/10 minutes and 1,500 g/10 minutes when theethylene acrylic acid salt is totally neutralized, and wherein theethylene acrylic acid salt has a melt index of between 1,000 g/10minutes and 1,400 g/10 minutes when the ethylene acrylic acid salt isneutralized at a rate of 70 to 99%.
 2. The aqueous suspension ordispersion of mineral matter according to claim 1, wherein the salt ofthe ethylene acrylic acid is present at a dry weight percent of 0.2 to2% based on the dry weight of mineral matter.
 3. The aqueous suspensionor dispersion of mineral matter according to claim 1, wherein the amineincludes one primary amine.
 4. The aqueous suspension or dispersion ofmineral matter according to claim 1, wherein the amine is analkanolamine.
 5. The aqueous suspension or dispersion of mineral matteraccording to claim 1, wherein the amine is 2-amino-2-methyl-1-propanoland/or dimethylethanolamine.
 6. The aqueous suspension or dispersion ofmineral matter according to claim 1, wherein the amine is2-amino-2-methyl-1-propanol.
 7. The aqueous suspension or dispersion ofmineral matter according to claim 1, wherein the amine isdimethylethanolamine.
 8. The aqueous suspension or dispersion of mineralmatter according to claim 1, having a dry weight of greater than 70%based on the total weight of the aqueous suspension or dispersion ofmineral matter.
 9. The aqueous suspension or dispersion of mineralmatter according to claim 1, having a dry weight of greater than 75%based on the total weight of the aqueous suspension or dispersion ofmineral matter.
 10. The aqueous suspension or dispersion of mineralmatter according to claim 1, having a dry weight of between 75 and 78%based on the total weight of the aqueous suspension or dispersion ofmineral matter.
 11. The aqueous suspension or dispersion of mineralmatter according to claim 1, wherein the mineral matter comprisesnatural and/or precipitated calcium carbonate.
 12. The aqueoussuspension or dispersion of mineral matter according to claim 1, whereinthe mineral matter comprises natural calcium carbonate.
 13. The aqueoussuspension or dispersion of mineral matter according to claim 1, whereinthe mineral matter includes, in addition to calcium carbonate, at leastone other mineral matter selected from a dolomite, a bentonite, akaolin, talc, cement, gypsum, lime, magnesia, titanium dioxide, satinwhite, aluminium trioxide, aluminium trihydroxide, a silica, mica, atalc-calcium carbonate blend, a calcium carbonate-kaolin blend, a blendof calcium carbonate with aluminium trihydroxide or aluminium trioxide,a blend of calcium carbonate with a synthetic or natural fiber, amineral costructure, a talc-calcium carbonate costructure, or atalc-titanium dioxide costructure, or any blend thereof.
 14. The aqueoussuspension or dispersion of mineral matter according to claim 1, whereinthe mineral matter comprises greater than or equal to 70% of calciumcarbonate based on the total dry weight of the mineral matter.
 15. Theaqueous suspension or dispersion of mineral matter according to claim 1,wherein the mineral matter has an average diameter of less than 15 μm.16. The aqueous suspension or dispersion of mineral matter according toclaim 1, wherein the mineral matter has an average diameter of less than5 μm.
 17. The aqueous suspension or dispersion of mineral matteraccording to claim 1, wherein the mineral matter has an average diameterof between 0.3 and 1.7 μm.
 18. The aqueous suspension or dispersion ofmineral matter according to claim 1, wherein the mineral matter has anaverage diameter of between 0.9 and 0.9 μm.
 19. The aqueous suspensionor dispersion of mineral matter according to claim 1, wherein greaterthan 60% of particles of the mineral matter has a diameter of less than2 μm.
 20. The aqueous suspension or dispersion of mineral matteraccording to claim 1, wherein greater than 90% of particles of themineral matter has a diameter of less than 2 μm.
 21. The aqueoussuspension or dispersion of mineral matter according to claim 1, whereingreater than 99% of particles of the mineral matter has a diameter ofless than 2 μm.
 22. The aqueous suspension or dispersion of mineralmatter according to claim 1, having a Brookfield viscosity of less than1,000 mPa·s measured at 100 rpms at 25° C.
 23. The aqueous suspension ordispersion of mineral matter according to claim 1, having a Brookfieldviscosity of less than 500 mPa·s measured at 100 rpms at 25° C.
 24. Theaqueous suspension or dispersion of mineral matter according to claim 1,having a Brookfield viscosity of between 100 and 300 mPa·s measured at100 rpms at 25° C.
 25. The aqueous suspension or dispersion of mineralmatter according to claim 1, wherein the salt of ethylene acrylic acidis a salt soluble in an aqueous medium.
 26. The aqueous suspension ordispersion of mineral matter according to claim 1, wherein the ethyleneacrylic acid salt has a melt index of between 200 g/10 minutes and 300g/10 minutes when the ethylene acrylic acid salt is totally neutralized.27. The aqueous suspension or dispersion of mineral matter according toclaim 1, which further comprises a dispersing and/or grinding aid agent.28. The aqueous suspension or dispersion of mineral matter according toclaim 1, wherein the dispersing and/or grinding aid agent is present ata dry weight percent of 0.1 to 2% based on the dry weight of the mineralmatter.
 29. The aqueous suspension or dispersion of mineral matteraccording to claim 27, wherein the dispersing agent and/or grinding aidagent is a homopolymer of acrylic acid and/or a copolymer of acrylicacid with a water-soluble monomer selected from methacrylic acid, maleicacid, itaconic acid, crotonic acid, fumaric acid, isocrotonic acid,aconitic acid, mesaconic acid, sinapic acid, undecylenic acid, angelicacid, canellic acid and/or 2-acrylamido 2-methyl propane sulfonic acidin acid form or partially neutralized, or acrylamide, methylacrylamide,an ester of an acrylic or methacrylic acid, acrylate phosphate, ethylenemethacrylate, propylene glycol, vinylpyrrolidone, vinylcaprolactame,vinyl acetate, sodium styrene sulfonate, allylamine, or derivativethereof.